Incidence of Chalara elegans in groundnut seed samples and seed transmission of blackhull.
The incidence of C. elegans (Thielaviopsis basicola) was determined in 7 commercial groundnut seed samples from the Vaalharts area of South Africa. It was demonstrated that 1.19% of the seeds were infected by the pathogen. Surface contamination of visually healthy seeds from the same samples was confirmed by testing seed washings for viable propagules of T. basicola on raw carrot discs. Naturally infected seed planted in autoclaved soil in the greenhouse resulted in 34.4% of the plants being severely diseased. It is concluded that seed-borne inoculum may be an important factor in the transmission of this disease.